The government of Japan is a constitutional monarchy whereby the power of the Emperor is limited and is relegated primarily to ceremonial duties. Like in many other states, the Government is divided into three branches: the Executive branch, the Legislative branch and the Judicial branch, as defined by the current post-war Constitution of Japan. The Constitution defines the Government to be in a unitary form of a parliamentary system. Local governments are established as an act of devolution, under the Local Autonomy Law. The throne of the Emperor is retained, even though popular sovereignty is adopted. Enacted as a revision to the pre-war Constitution of the Empire of Japan, it enables a democratic type of governance whereby both the legislative and executive branches of the Government are held accountable to each other; a feature known as the Fusion of powers. The powers of the executive branch, which is explicitly vested in the Cabinet, must enjoy the support and confidence to be in office by the organ of the legislative branch, the National Diet. Likewise, the Prime minister, as the head of the Cabinet, has the power to dissolve the House of Representatives, one of the two houses of the Diet. However, unlike parliamentary republics, the executive branch do not conceptually derive legitimacy from the parliament in the form of parliamentary sovereignty, but instead derive its authority from its people through a parallel voting system. Thus, the National Diet is, under the Constitution, known as "the highest organ of state power"; strictly reflecting the sovereignty of the people as represented by the Diet. While the executive and legislative branches are intermingled together, the judicial branch is, however, strictly separated from the other branches. Its separation is guaranteed by the Constitution, and is stated as: "no extraordinary tribunal shall be established, nor shall any organ or agency of the Executive be given final judicial power"; a feature known as the Separation of Powers. The Emperor acts as the ceremonial head of state, and is defined by the Constitution to be "the symbol of the State and of the unity of the people". The Prime Minister is the head of government, and is formally appointed to office by the Emperor after being designated by the National Diet.